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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
commit | 19f4f86bfed21c5326ed2acebe1163f3a83e832b (patch) | |
tree | d59b9989ce55ed23693e80974d94c856f1c2c8b1 /src/libsystemd-network/dhcp-option.c | |
parent | Initial commit. (diff) | |
download | systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.tar.xz systemd-19f4f86bfed21c5326ed2acebe1163f3a83e832b.zip |
Adding upstream version 241.upstream/241upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/libsystemd-network/dhcp-option.c')
-rw-r--r-- | src/libsystemd-network/dhcp-option.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c new file mode 100644 index 0000000..ad3f925 --- /dev/null +++ b/src/libsystemd-network/dhcp-option.c @@ -0,0 +1,274 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ +/*** + Copyright © 2013 Intel Corporation. All rights reserved. +***/ + +#include <errno.h> +#include <stdint.h> +#include <stdio.h> +#include <string.h> + +#include "alloc-util.h" +#include "utf8.h" +#include "strv.h" + +#include "dhcp-internal.h" + +static int option_append(uint8_t options[], size_t size, size_t *offset, + uint8_t code, size_t optlen, const void *optval) { + assert(options); + assert(offset); + + if (code != SD_DHCP_OPTION_END) + /* always make sure there is space for an END option */ + size--; + + switch (code) { + + case SD_DHCP_OPTION_PAD: + case SD_DHCP_OPTION_END: + if (size < *offset + 1) + return -ENOBUFS; + + options[*offset] = code; + *offset += 1; + break; + + case SD_DHCP_OPTION_USER_CLASS: { + size_t len = 0; + char **s; + + STRV_FOREACH(s, (char **) optval) + len += strlen(*s) + 1; + + if (size < *offset + len + 2) + return -ENOBUFS; + + options[*offset] = code; + options[*offset + 1] = len; + *offset += 2; + + STRV_FOREACH(s, (char **) optval) { + len = strlen(*s); + + if (len > 255) + return -ENAMETOOLONG; + + options[*offset] = len; + + memcpy_safe(&options[*offset + 1], *s, len); + *offset += len + 1; + } + + break; + } + default: + if (size < *offset + optlen + 2) + return -ENOBUFS; + + options[*offset] = code; + options[*offset + 1] = optlen; + + memcpy_safe(&options[*offset + 2], optval, optlen); + *offset += optlen + 2; + + break; + } + + return 0; +} + +int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset, + uint8_t overload, + uint8_t code, size_t optlen, const void *optval) { + size_t file_offset = 0, sname_offset =0; + bool file, sname; + int r; + + assert(message); + assert(offset); + + file = overload & DHCP_OVERLOAD_FILE; + sname = overload & DHCP_OVERLOAD_SNAME; + + if (*offset < size) { + /* still space in the options array */ + r = option_append(message->options, size, offset, code, optlen, optval); + if (r >= 0) + return 0; + else if (r == -ENOBUFS && (file || sname)) { + /* did not fit, but we have more buffers to try + close the options array and move the offset to its end */ + r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL); + if (r < 0) + return r; + + *offset = size; + } else + return r; + } + + if (overload & DHCP_OVERLOAD_FILE) { + file_offset = *offset - size; + + if (file_offset < sizeof(message->file)) { + /* still space in the 'file' array */ + r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval); + if (r >= 0) { + *offset = size + file_offset; + return 0; + } else if (r == -ENOBUFS && sname) { + /* did not fit, but we have more buffers to try + close the file array and move the offset to its end */ + r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL); + if (r < 0) + return r; + + *offset = size + sizeof(message->file); + } else + return r; + } + } + + if (overload & DHCP_OVERLOAD_SNAME) { + sname_offset = *offset - size - (file ? sizeof(message->file) : 0); + + if (sname_offset < sizeof(message->sname)) { + /* still space in the 'sname' array */ + r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval); + if (r >= 0) { + *offset = size + (file ? sizeof(message->file) : 0) + sname_offset; + return 0; + } else { + /* no space, or other error, give up */ + return r; + } + } + } + + return -ENOBUFS; +} + +static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload, + uint8_t *message_type, char **error_message, dhcp_option_callback_t cb, + void *userdata) { + uint8_t code, len; + const uint8_t *option; + size_t offset = 0; + + while (offset < buflen) { + code = options[offset ++]; + + switch (code) { + case SD_DHCP_OPTION_PAD: + continue; + + case SD_DHCP_OPTION_END: + return 0; + } + + if (buflen < offset + 1) + return -ENOBUFS; + + len = options[offset ++]; + + if (buflen < offset + len) + return -EINVAL; + + option = &options[offset]; + + switch (code) { + case SD_DHCP_OPTION_MESSAGE_TYPE: + if (len != 1) + return -EINVAL; + + if (message_type) + *message_type = *option; + + break; + + case SD_DHCP_OPTION_ERROR_MESSAGE: + if (len == 0) + return -EINVAL; + + if (error_message) { + _cleanup_free_ char *string = NULL; + + /* Accept a trailing NUL byte */ + if (memchr(option, 0, len - 1)) + return -EINVAL; + + string = strndup((const char *) option, len); + if (!string) + return -ENOMEM; + + if (!ascii_is_valid(string)) + return -EINVAL; + + free_and_replace(*error_message, string); + } + + break; + case SD_DHCP_OPTION_OVERLOAD: + if (len != 1) + return -EINVAL; + + if (overload) + *overload = *option; + + break; + + default: + if (cb) + cb(code, len, option, userdata); + + break; + } + + offset += len; + } + + if (offset < buflen) + return -EINVAL; + + return 0; +} + +int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t cb, void *userdata, char **_error_message) { + _cleanup_free_ char *error_message = NULL; + uint8_t overload = 0; + uint8_t message_type = 0; + int r; + + if (!message) + return -EINVAL; + + if (len < sizeof(DHCPMessage)) + return -EINVAL; + + len -= sizeof(DHCPMessage); + + r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata); + if (r < 0) + return r; + + if (overload & DHCP_OVERLOAD_FILE) { + r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata); + if (r < 0) + return r; + } + + if (overload & DHCP_OVERLOAD_SNAME) { + r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata); + if (r < 0) + return r; + } + + if (message_type == 0) + return -ENOMSG; + + if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE)) + *_error_message = TAKE_PTR(error_message); + + return message_type; +} |